Method and compositions for protecting maize against injury from the interaction of an organophosphate insecticide-nematicide and an AHAS-inhibiting herbicide using lactidichlor

ABSTRACT

There is provided a method for inhibiting or preventing injury to a corn plant caused by the synergistic interaction of an organophosphate compound employed for the protection of the plant against attack by insects and nematodes and the use of an acetohydroxyacid synthase-inhibiting compound employed for the control of undesirable weed species in the locus of the plant comprising the application of an effective amount of naphthalic anhydride, the dipotassium salt of naphthalic acid, dicamba, 2,4-D, dichlormid, butyl 2-[(5-chloro-8-quinolyl)oxy]acetimidate, butyl [(5-chloro-8-quinolyl)oxy]acetate, 1-methylhexyl 2-[(5-chloro-8-quinolyl)oxy]acetate or 1-carbethoxyethyl-3,6-dichloro-2-methoxybenzoate. There is also provided a safened insecticidal composition.

This is a continuation of application Ser. No. 07/733,511, filed on Jul.22, 1991, abandoned.

BACKGROUND OF THE INVENTION

This invention relates to methods and compositions for eliminating orpreventing injury to a corn plant caused by the interaction of two ormore pesticides applied to the plant in combination, eithersimultaneously or sequentially. Of particular concern are synergisticresponses which occur on a single plant species. Synergistic responsesobtained with combinations of herbicides, insecticides and fungicidesare described as the combined action of two components of a mixture suchthat the total effect is greater or more prolonged than the sum of theeffects of the two components taken independently.

More particularly, the invention provides methods and compositions foreliminating or preventing injury to a crop plant resulting from theinteraction of an organophosphate pesticide and an acetohydroxyacidsynthase-inhibiting herbicide. More particularly, this invention relatesto methods of and compositions for preventing, inhibiting orameliorating injury to plants resulting from the interaction of0,0-diethyl S-[(ethylthio)methyl]phosphorodithioate (phorate) or0,0-diethyl S-{[(1,1-dimethylethyl)thio]-methyl}phosphorodithioate(terbufos) and a sulfonylurea herbicide such as nicosulfuron orprimisulfuron or an imidazolinone herbicide such as imazethapyr,imazamethapyr or imazaquin.

The ever increasing demands for greater quantities and improved qualityof food to feed the expanding human population around the world hasdriven plant science agriculturalists to maximize crop yield and productquality for every hectare of land under cultivation. To this end,knowledgeable farm practitioners have found it advantageous to protecttheir crops from the time of planting through harvest and beyond againstattack, infestation or encroachment by all types of pests including:insects, acarina, bacteria, fungi, nematodes and undesirable plantspecies. Thus, to achieve the desired protection it has become a rathercommon practice in the farming industry to use a multiplicity of pestcontrol agents, applied either simultaneously or sequentially, toprovide concurrent and continuous protection for the treated crop plant.

In many instances, it has been found that combination treatments affordplant protection against a variety of pests with a single application ofcombined pesticides or with simultaneous or sequential applications oftwo or more pesticides applied to the planted and/or growing crop. Inpractice, there are many known instances of considerable modificationsin the biological activity of one pesticide brought about by the prior,simultaneous or sequential application of another pesticide to the sametarget species. When this occurs it is commonly referred to as an"interaction". As a result of pesticide interactions, adverse effectscan occur; and the responses of target species such as corn plants tothe combined applications of two or more pesticides are not predictablefrom the effect of each pesticide applied alone. Said interactions aredescribed as antagonistic when the net effect is a decrease in thebiological activity and synergistic when the net effect is anenhancement of biological activity. In other words, a synergisticinteraction of a pesticide combination is a more than additive toxicaction of two or more pesticides when used together. Pesticidecombination applications which result in a synergistic interaction areherein described as synergistic pesticide combinations.

For the past two decades, terbufos and phorate have been used for thecontrol of soilborne pests and as systemic insecticides. These compoundshave been used successfully for the control of soilborne andleaf-feeding pests and have been utilized in conjunction with a varietyof other pesticides without reports of undesirable interactions. Thus,it is surprising to find that with the recent introduction of certainAHAS inhibiting herbicides (for instance, sulfonylureas such asnicosulfuron and primisulfuron) there appears to be a synergisticinteraction observed in corn plants which have been treated at plantingwith a soil insecticide such as disulfoton, chlorpyrifos, fonofos,phorate or terbufos and thereafter treated early postemergence or whenthe plants are in the seedling stage, i.e. about the three to five leafstage, with nicosulfuron or primisulfuron.

It is believed that the synergistic interaction of certainorganophosphate compounds with nicosulfuron or primisulfuron occurs whenan organophosphate compound is taken into the root system of a plant andinhibits the plant's ability to metabolize the sulfonylurea compound.This inhibition permits the sulfonylurea compound to accumulate in theplant tissue and reach levels which can cause significant injury to theplant.

It is, therefore, an object of this invention to provide methods andcompositions for inhibiting, preventing or ameliorating injury to a cornplant resulting from the synergistic interaction of two or morechemicals applied to said plant or the locus in which it is planted orgrowing.

A further object of this invention is to provide methods andcompositions for protecting a corn plant from attack by soilborne pestsand preventing incursion into the corn growing area of undesirable plantspecies while inhibiting or preventing injury to the corn plant due tothe synergistic interaction between an organophosphate insecticide andan AHAS-inhibiting herbicide.

DESCRIPTION OF THE INVENTION

Surprisingly it has been found that the pesticide interaction of anorganophosphate insecticide and an AHAS-inhibiting herbicide can besafened by the addition of a third chemical. The third chemical isherein referred to as a safener compound. The present invention includesa method of protecting corn plants from injury resulting from thesynergistic interaction of a systemic organophosphate insecticide suchas terbufos or phorate and an AHAS-inhibiting herbicide such asnicosulfuron or primisulfuron by applying an effective amount of asafener compound selected from the group consisting of 1,8-napthalicanhydride, the dipotassium salt of napthalic acid (herein referred to asNAK), 3,6-dichloro-2-methoxybenzoic acid (dicamba), 2,4-dichlorophenoxyacetic acid (2,4-D), dichloroacetamide compounds such asN,N-diallyl-2,2-dichloroacetamide (dichlormid), hydroxyquinolinecompounds such as butyl 2-[(5-chloro-8-quinolyl)oxy] acetimidate and1-carbethoxyethyl 3,6-dichloro-2-methoxybenzoate.

The organophosphate insecticide of the invention includes terbufos,phorate, fonofos, disulfoton, chlorpyrifos and the like, preferablyterbufos or phorate. The AHAS-inhibiting herbicide includes a sulfonylurea herbicide, preferably nicosulfuron or primisulfuron and animidazolinone herbicide, preferably imazethapyr, imazamethapyr orimazaquin.

The safener compounds of the present invention have a variety of usesbut previously have not been used for safening maize from injury causedby a synergistic pesticide interaction. Suitable safener compounds ofthe invention include: 1-carbethoxyethyl 3,6-dichloro-2-methoxybenzoate,1,8-naphthalic anhydride, NAK, dicamba and 2,4-D. Further suitablesafener compounds include dichloroacetamide compounds andhydroxyquinoline compounds. Dichloroacetamide compounds include4-(dichloroacetyl)-3,4-dihydro-3-methyl-2H-1,4-benzoxazine,1-dichloroacetyl-hexahydro-3,3-8α-trimethyl-pyrrolo-[1,2-α]pyrimidin-6-(2H)-one,2-dichloromethyl-2-methyl-1,3-dioxolane,N-dichloroacetyl-1-oxa-4-aza-spiro-4,5-decane, dichlormid and the like.Hydroxyquinoline compounds include butyl2-[(5-chloro-8-quinolyl)oxy]acetimidate, butyl[(5-chloro-8-quinolyl)oxy]acetate,1-methylhexyl[(5-chloro-8-quinolyl)oxy]acetate and the like.

The safener compound can be applied in a variety of ways. For instance,the safener compound can be applied (1) to the soil, (2) to the cropplant seed, (3) to the crop plant or (4) in combination with theinsecticide. If the safener compound is applied to the soil, it can beapplied before, in conjunction with or after the insecticide. Thesafener may be applied to the soil in-furrow, preplant incorporated orpreemergence.

In another embodiment of the present invention, the safener compound maybe applied to the corn plant seed. Conventional seed treatmenttechniques using the safener compounds of the present invention may beemployed to give satisfactory safening of the pesticide interaction.

If the safener compound is applied postemergence to the corn plants,generally it may be applied as a foliar spray. This applicationtechnique may be employed prior to herbicidal treatment or at the sametime as herbicidal treatment. While it is contemplated that the safenercompound may be applied a short time after application of herbicide, itis generally less effective, since some injury from the synergisticpesticide interaction may result. For convenience, when applying thesafener compound postemergence, it is best to apply it simultaneouslywith the herbicide such as in a tank mix.

Further, the safener compound may be applied in combination with theorganophosphate insecticide. For example, the formulated insecticide maybe coated with the safener compound. It is also contemplated that thesafener compounds may be premixed with the technical insecticide such asterbufos or phorate prior to the final formulation. For example, thepremixed soil insecticide-nematicide and safener compound may be applieddirectly to a suitable carrier such as clay, attapulgite, BIODAC®,montmorillonite and the like, or may be homogeneously mixed with aplastic formulation such as a polyvinyl chloride or a starch-likeformulation.

Compositions are provided in which an effective amount of the safenercompound is intimately dispersed in an inert carrier or liquid diluent.An inert carrier is one that will not react with the safener compoundand is suitable for agronomic use.

Typical compositions of the invention include wettable powders, dusts,granules, sprays and the like. The inventive compositions are suitablefor application to the soil, to the formulated insecticide or to thecorn seed either directly or after an intermediate dilution or blendingstep.

In order to facilitate a further understanding of the invention, thefollowing examples are presented primarily for the purpose ofillustrating certain more specific details thereof. The invention is notto be deemed limited thereby except as defined in the claims.

EXAMPLE 1

Evaluation of 1,8-naphthalic anhydride as a seed treatment on thesynergistic interaction between two pesticides

Corn seeds (Pioneer 3475) are coated with naphthalic anhydride(ADVANTAGE, manufactured by FMC corporation, 91% active ingredient).Seeds are coated with naphthalic anhydride at rates ranging from 0.05grams per 100 grams seed (equal to 0.05% by seed weight), to 0.5 gramsper 100 grams seed (equal to 0.5% by seed weight).

Experiments are conducted in sterilized loamy sand soil containing 5%organic matter. Soil is placed in 10-inch×10-inch×2-inch shallow plasticflats, and thoroughly moistened. Two six-inch furrows are made in eachflat, into each furrow is placed five corn seeds, either coated oruncoated with the safener. The organophosphate insecticide terbufosmanufactured by American Cyanamid Company is applied to one furrow asthe 15% granular formulation (COUNTER® 15G) at a rate equivalent to 1.0kg/ha of active ingredient; the other furrow is left untreated.

Plants are sprayed postemergence with a herbicide at about the 2-4 leaf(5-8 inch) stage of growth. A commercial formulation of primisulfuronwhich contains 75% of active ingredient (BEACON® 75 DF, manufactured byCiba-Geigy Co), is diluted with water to provide the equivalent of 0.04kg/ha of active ingredient to the foliage when applied through a spraynozzle operating at 40 psi for a predetermined time. The herbicide spraysolution contains 0.25% of the spray adjuvant CHARGER E, an alkylarylpolyethoxyethanol and N-butanol 80% non-ionic wetting agent manufacturedby Blue Ribbon Products Co.

After spraying, flats are then placed on greenhouse benches, watered andcared for in accordance with conventional greenhouse procedures. From2-4 weeks after treatment, the tests are terminated and each flat isexamined and rated by measuring the height of the foliage. The testresults are averaged and expressed as a percent growth reductioncompared to an untreated check, using the following formula: ##EQU1##The data are shown in Table I.

                  TABLE I                                                         ______________________________________                                                                     % Growth                                         Treatment        Rate (kg/ha)                                                                              Reduction                                        ______________________________________                                        Untreated check  0.00        0                                                Terbufos         1.00        2                                                Primisulfuron    0.04         0*                                              Terbufos × Primisulfuron                                                                 1.0 × 0.04                                                                          68                                               Terbufos × Primisulfuron +                                                               1.0 × 0.04                                             naphthalic anhydride                                                                           0.05% seed wt                                                                             3                                                Terbufos × Primisulfuron +                                                               1.0 × 0.04                                             naphthalic anhydride                                                                           0.10% seed wt                                                                             10                                               Terbufos × Primisulfuron +                                                               1.0 × 0.04                                             naphthalic anhydride                                                                           0.25% seed wt                                                                             8                                                Terbufos × Primisulfuron +                                                               1.0 × 0.04                                             naphthalic anhydride                                                                           0.50% seed wt                                                                             9                                                ______________________________________                                         Shoot height of the untreated check was 82.6 cm                               *Growth was 2% greater than the untreated check                          

EXAMPLE 2

Evaluation of 1,8-naphthalic anhydride applied directly to theinsecticide on the synergistic interaction between two pesticides

A mixture of naphthalic anhydride and a wettable powder formulationcontaining 5% Marasperse CBO, a sodium lignin sulfonate manufactured byReed-Lignin, 1% Igepon T-77, an N-methyl-N-oleoyltaurate manufactured byGAF Industries, and 94% Attaclay, attapulgite fines manufactured byEnglehardt is prepared to provide a formulation containing 20% activeingredient. This mixture is applied to terbufos, formulated as 15%active ingredient on Creek-o-Nite clay granules (COUNTER® 15G), byshaking thoroughly. Amounts of the wettable powder equal to 6, 12, 24and 50 milligrams, are applied to 0.125 grams of COUNTER® 15G to providein-furrow rates equivalent to 1.0 kg/ha terbufos and 0.063-0.5 kg/hanaphthalic anhydride.

Experiments are conducted in either a plano silt loam soil or a loamysand soil containing 5% organic matter. Soil is placed in10-inch×10-inch×2-inch shallow plastic flats, and thoroughly moistened.Two six-inch furrows are made in each flat, five corn seeds are placedin each furrow. Terbufos is applied to one furrow either as theuntreated 15% granular formulation (COUNTER® 15G), or the treatedgranular formulation containing naphthalic anhydride.

The furrows are closed and the plants are allowed to grow to about the2-4 leaf stage at which time the plants are sprayed postemergence withthe herbicide primisulfuron as described in Example 1.

After 2-4 weeks of greenhouse care, the tests are terminated and theplants evaluated as described in Example 1.

The results are shown in Table II.

                  TABLE II                                                        ______________________________________                                                             %                                                                             Growth Reduction                                                                    (A)       (B)                                                                 Plano Silt                                                                              Loamy                                    Treatment       Rate (kg/ha)                                                                             Loam      Sand                                     ______________________________________                                        Untreated check 0.00       0         0                                        Terbufos        1.00       11        6                                        Primisulfuron   0.04       9         12                                       Terbufos × Primisulfuron                                                                1.0 × 0.04                                                                         57        33                                       Terbufos × Primisulfuron +                                                              1.0 × 0.04                                              naphthalic anhydride                                                                          0.063      34        18                                       Terbufos × Primisulfuron +                                                              1.0 × 0.04                                              naphthalic anhydride                                                                          0.125      34        20                                       Terbufos × Primisulfuron +                                                              1.0 × 0.04                                              naphthalic anhydride                                                                          0.25       19        10                                       Terbufos × Primisulfuron +                                                              1.0 × 0.04                                              naphthalic anhydride                                                                          0.50       17        14                                       ______________________________________                                         (A) Shoot height of the untreated check was 41.6 cm                           (B) Shoot height of the untreated check was 93.2 cm                      

EXAMPLE 3

Evaluation of a foliar application of the dipotassium salt of naphthalicacid (NAK) on the synergistic interaction between two pesticides

Experiments are conducted in a loamy sand soil containing 5% organicmatter. Soil is placed in 10-inch×10-inch×2-inch shallow plastic flats,and thoroughly moistened. Two six-inch furrows are made in each flat,into each furrow are placed five corn seeds. The organophosphateinsecticide, terbufos, is applied to one furrow as the 15% granularformulation (COUNTER® 15G) at a rate equivalent to 1 kg/ha; the otherfurrow is left untreated.

When plants have reached the 2-4 leaf stage, they are sprayed with anaqueous solution containing 0.25% CHARGER E surfactant, the dipotassiumsalt of naphthalic acid (NAK) and the sulfonylurea herbicideprimisulfuron in sufficient quantities to provide 0-1.0 kg/ha of NAK and0.04 kg/ha of primisulfuron when applied to the plants with a 40 psinozzle. After spraying, plants are maintained in a greenhouse, and thetest evaluated as described in Example 1.

The results are reported in Table III.

                  TABLE III                                                       ______________________________________                                                                       % Growth                                       Treatment          Rate (kg/ha)                                                                              Reduction                                      ______________________________________                                        Untreated check    0.00        0                                              Terbufos           1.00        3                                              Primisulfuron      0.04        13                                             Terbufos × Primisulfuron                                                                   1.0 × 0.04                                                                          41                                             Terbufos × Primisulfuron +                                                                 1.0 × 0.04                                           NAK                0.50        15                                             Terbufos × Primisulfuron +                                                                 1.0 × 0.04                                           NAK                0.75        13                                             Terbufos × Primisulfuron +                                                                 1.0 × 0.04                                           NAK                1.00%       16                                             ______________________________________                                         Shoot height of the untreated check was 73.2 cm                          

EXAMPLE 4

Evaluation of dichlormid as a seed treatment on the synergisticinteraction between two pesticides

Corn seeds (Pioneer 3475) are treated with the safener dichlormid(2,2-dichloro-N-N-di-2-propenylacetamide) by first making a stocksolution of the safener in 2.5 milliters of an acetone:dimethylformamide(10:1) mixture. Aliquots of the stock solution ranging from 62.5microliters to 1.0 milliliter are added to 10 grams of corn seed andshaken thoroughly to provide safener seed treatment rates equivalent to0.025%-0.4% by seed weight.

Treated and untreated seeds are planted in 6" furrows made in a loamysand soil containing 5% organic matter. One-half of the furrows aretreated with the insecticide terbufos, as described in Example 1.

The plants are grown to the 2-4 leaf stage and are treated postemergencewith the herbicide primisulfuron as described in Example 1. After 2-4weeks of greenhouse care the plants are evaluated as described inExample 1.

The results are shown in Table IV.

                  TABLE IV                                                        ______________________________________                                                                     % Growth                                         Treatment        Rate (kg/ha)                                                                              Reduction                                        ______________________________________                                        Untreated check  0.00         0                                               Terbufos         1.00         O*                                              Primisulfuron    0.04        13                                               Terbufos × Primisulfuron                                                                 1.0 × 0.04                                                                          45                                               Terbufos × Primisulfuron +                                                               1.0 × 0.04                                             Dichlormid       0.025% seed wt                                                                            14                                               Terbufos × Primisulfuron +                                                               1.0 × 0.04                                             Dichlormid       0.05% seed wt                                                                             21                                               Terbufos × Primisulfuron +                                                               1.0 × 0.04                                             Dichlormid       0.10% seed wt                                                                             22                                               Terbufos × Primisulfuron +                                                               1.0 × 0.04                                             Dichlormid       0.02% seed wt                                                                             17                                               Terbufos × Primisulfuron +                                                               1.0 × 0.04                                             Dichlormid       0.4% seed wt                                                                              24                                               ______________________________________                                         Shoot height of the untreated check was 80.6 cm                               *Growth was 6% greater than the untreated check                          

EXAMPLE 5

Evaluation of dichlormid applied directly to the soil on the synergisticinteraction between two pesticides

Experiments are conducted in a loamy sand soil containing 5% organicmatter. Soil is placed in 10-inch×10-inch×2-inch shallow plastic flats,and thoroughly moistened. Two six-inch furrows are made in each flat,into each are placed five corn seeds. The organophosphate insecticideterbufos is applied to one furrow as the 15% granular formulation(COUNTER® 15G) at a rate equivalent to 1.0 kg/ha; the other furrow isleft untreated. The furrows are closed.

The safener dichlormid is applied to the soil surface by spraying withan 80% acetone solution containing dichlormid in sufficient quantitiesto provide a rate equivalent to 0-1.0 kg/ha when applied with a 40 psinozzle. After spraying, the soil surface is covered with a thin layer ofuntreated soil.

When the plants have reached the 2-4 leaf stage, they are sprayed withthe herbicide primisulfuron as described in Example 1.

The plants are given greenhouse care for 2-4 weeks and are evaluated asdescribed in Example 1.

The results are shown in Table V.

                  TABLE V                                                         ______________________________________                                                                       % Growth                                       Treatment          Rate (kg/ha)                                                                              Reduction                                      ______________________________________                                        Untreated check    0.00        0                                              Terbufos           1.00         O*                                            Primisulfuron      0.04         0**                                           Terbufos × Primisulfuron                                                                   1.0 × 0.04                                                                          33                                             Terbufos × Primisulfuron +                                                                 1.0 × 0.04                                           Dichlormid         0.032       28                                             Terbufos × Primisulfuron +                                                                 1.0 × 0.04                                           Dichlormid         0.063       22                                             Terbufos × Primisulfuron +                                                                 1.0 × 0.04                                           Dichlormid         0.125       11                                             Terbufos × Primisulfuron +                                                                 1.0 × 0.04                                           Dichlormid         0.25        2                                              Terbufos × Primisulfuron +                                                                 1.0 × 0.04                                           Dichlormid         0.50        1                                              Terbufos × Primisulfuron +                                                                 1.0 × 0.04                                           Dichlormid         0.75        8                                              Terbufos × Primisulfuron +                                                                 1.0 × 0.04                                           Dichlormid         1.00        8                                              ______________________________________                                         Shoot height of the untreated check was 79.5 cm                               *Growth was 16% greater than the untreated check                              **Growth was 3% greater than the untreated check                         

EXAMPLE 6

Evaluation of a foliar application of dichlormid on the synergisticinteraction between two pesticides

The procedure used is as described in Example 3, except that plants aresprayed with an aqueous solution containing 0.25% CHARGER E surfactant,dichlormid, and the sulfonylurea herbicide primisulfuron in sufficientquantities to provide 0-1.0 kg/ha of dichlormid and 0.04 kg/ha ofprimisulfuron when applied to the plants with a 40 psi nozzle.

The results are shown in Table VI.

                  TABLE VI                                                        ______________________________________                                                                       % Growth                                       Treatment          Rate (kg/ha)                                                                              Reduction                                      ______________________________________                                        Untreated check    0.00         0                                             Terbufos           1.00         O*                                            Primisulfuron      0.04         6                                             Terbufos × Primisulfuron                                                                   1.0 × 0.04                                                                          67                                             Terbufos × Primisulfuron +                                                                 1.0 × 0.04                                           Dichlormid         0.063       59                                             Terbufos × Primisulfuron +                                                                 1.0 × 0.04                                           Dichlormid         0.125       35                                             Terbufos × Primisulfuron +                                                                 1.0 × 0.04                                           Dichlormid         0.025       31                                             Terbufos × Primisulfuron +                                                                 1.0 × 0.04                                           Dichlormid         0.50        17                                             Terbufos × Primisulfuron +                                                                 1.0 × 0.04                                           Dichlormid         0.75        18                                             Terbufos × Primisulfuron +                                                                 1.0 × 0.04                                           Dichlormid         1.00         3                                             ______________________________________                                         Shoot height of the untreated check was 80.6 cm                               *Growth was 6% greater than the untreated check                          

EXAMPLE 7

Evaluation of 1-carbethoxyethyl 3,6-dichloro-2-methoxybenzoate as a seedtreatment on the synergistic interaction between two pesticides

The procedure used is as described in Example 4, except that seeds aretreated with 1-carbethoxyethyl 3,6-dichloro-2-methoxybenzoate prior toplanting.

The results are shown in Table VII.

                  TABLE VII                                                       ______________________________________                                                                       % Growth                                       Treatment        Rate (kg/ha   Reduction                                      ______________________________________                                        Untreated check  0.00           0                                             Terbufos         1.00           O*                                            Primisulfuron    0.04            0**                                          Terbufos × Primisulfuron                                                                 1.0 × 0.04                                                                            38                                             Terbufos × Primisulfuron +                                                               1.0 × 0.04                                             3,6-dichloro-2-methoxy-                                                                        0.025% seed wt                                                                              53                                             benzoic acid, 1-carboxy-                                                      ethyl ester                                                                   Terbufos × Primisulfuron +                                                               1.0 × 0.04                                             3,6-dichloro-2-methoxy-                                                                        0.05% seed wt 29                                             benzoic acid, 1-carboxy-                                                      ethyl ester                                                                   Terbufos × Primisulfuron +                                                               1.0 × 0.04                                             3,6-dichloro-2-methoxy-                                                                        0.10% seed wt 50                                             benzoic acid, 1-carboxy-                                                      ethyl ester                                                                   Terbufos × Primisulfuron +                                                               1.0 × 0.04                                             3,6-dichloro-2-methoxy-                                                                        0.2% seed wt  22                                             benzoic acid, 1-carboxy-                                                      ethyl ester                                                                   Terbufos × Primisulfuron +                                                               1.0 × 0.04                                             3,6-dichloro-2-methoxy-                                                                        0.4% seed wt  22                                             benzoic acid, 1-carboxy-                                                      ethyl ester                                                                   ______________________________________                                         Shoot height of the untreated check was 68.0 cm                               *Growth was 12% greater than the untreated check                              **Growth was 2% greater than the untreated check                         

EXAMPLE 8

Evaluation of the foliar application of 1-carbethoxyethyl3,6-dichloro-2-methoxybenzoate on the synergistic interaction betweentwo pesticides

The procedure used is the same as in Example 3, except that plants aresprayed with an aqueous solution containing 0.25% CHARGER E surfactant,1-carbethoxyethyl 3,6-dichloro-2-methoxybenzoate and the sulfonylureaherbicide primisulfuron in sufficient quantities to provide 0-0.5 kg/haof 1-carbethoxyethyl 3,6-dichloro-2-methoxybenzoate and 0.04 kg/ha ofprimisulfuron when applied to the plants with a 40 psi nozzle.

The results are shown in Table VIII.

                  TABLE VIII                                                      ______________________________________                                                                       % Growth                                       Treatment          Rate (kg/ha)                                                                              Reduction                                      ______________________________________                                        Untreated check    0.00        0                                              Terbufos           1.00        1                                              Primisulfuron      0.04        16                                             Terbufos × Primisulfuron                                                                   1.0 × 0.04                                                                          37                                             Terbufos × Primisulfuron +                                                                 1.0 × 0.04                                           1-carbethoxyethyl 3,6-                                                                           0.063       35                                             dichloro-2-methoxybenzoate                                                    Terbufos × Primisulfuron +                                                                 1.0 × 0.04                                           1-carbethoxyethyl 3,6-                                                                           0.125       27                                             dichloro-2-methoxybenzoate                                                    Terbufos × Primisulfuron +                                                                 1.0 × 0.04                                           1-carbethoxyethyl 3,6-                                                                           0.25        18                                             dichloro-2-methoxybenzoate                                                    Terbufos × Primisulfuron +                                                                 1.0 × 0.04                                           1-carbethoxyethyl 3,6-                                                                           0.50        21                                             dichloro-2-methoxybenzoate                                                    ______________________________________                                         Shoot height of the untreated check was 79.0 cm                          

EXAMPLE 9

Evaluation of a foliar application of a hydroxyquinoline compound on thesynergistic interaction between two pesticides

The procedure used is the same as described in Example 3, except thatplants are sprayed with a hydroxyquinoline compound, butyl2-[(5-chloro-8-qinolyl)oxy]acetimidate (compound A) or butyl[5-chloro-8-qunolyl)oxy]acetate (compound B) and the sulfonylureaherbicide, primisulfuron in sufficient quantities to provide 0-1.0 kg/haof a hydroxyquinoline compound and 0.04 kg/ha of primisulfuron whenapplied to the plants with a 40 psi nozzle.

The results are shown in Table IX.

                  TABLE IX                                                        ______________________________________                                                                       % Growth                                       Treatment          Rate (kg/ha)                                                                              Reduction                                      ______________________________________                                        Untreated check    0.00        0                                              Terbufos           1.00        3                                              Primisulfuron      0.04        13                                             Terbufos × Primisulfuron                                                                   1.0 × 0.04                                                                          41                                             Terbufos × Primisulfuron +                                                                 1.0 × 0.04                                           hydroxyquinoline   0.5         16                                             Compound A*                                                                   Terbufos × Primisulfuron +                                                                 1.0 × 0.04                                           hydroxyquinoline   0.75        24                                             Compound A*                                                                   Terbufos × Primisulfuron +                                                                 1.0 × 0.04                                           hydroxyquinoline   1.00        25                                             Compound A*                                                                   Terbufos × Primisulfuron +                                                                 1.0 × 0.04                                           hydroxyquinoline   0.5         22                                             Compound B**                                                                  Terbufos × Primisulfuron +                                                                 1.0 × 0.04                                           hydroxyquinoline   0.75        14                                             Compound B**                                                                  Terbufos × Primisulfuron +                                                                 1.0 × 0.04                                           hydroxyquinoline   1.00        17                                             Compound B**                                                                  ______________________________________                                         Shoot height of the untreated check was 73.2 cm                               *Butyl 2[(5chloro-8-quinolyl)oxy]acetimidate                                  **Butyl 2[(5chloro-8-quinolyl)oxy]acetate                                

EXAMPLE 10

Evaluation of a foliar application of 2,4-D on the synergisticinteraction between two pesticides

The procedure used is the same as described in Example 3, except thatthe plants are sprayed with 2,4-dichlorophenoxyacetic acid (2,4-D) asthe amine formulation and the herbicide primisulfuron in sufficientquantities to provide 0-0.75 kg/ha of 2,4-D and 0.02-0.04 kg/ha ofprimisulfuron when applied to the plants with a 40 psi nozzle. Theresults are reported in Table X.

                  TABLE X                                                         ______________________________________                                                                       % Growth                                       Treatment          Rate (kg/ha)                                                                              Reduction                                      ______________________________________                                        Untreated check    0.00        0                                              Terbufos           1.00        3                                              Primisulfuron      0.02        6                                              Terbufos × Primisulfuron                                                                   1.0 × 0.02                                                                          34                                             Terbufos × Primisulfuron +                                                                 1.0 × 0.02                                           2,4-D              0.25        22                                             Terbufos × Primisulfuron +                                                                 1.0 × 0.02                                           2,4-D              0.50        13                                             Terbufos × Primisulfuron +                                                                 1.0 × 0.02                                           2,4-D              0.75        18                                             Primisulfuron      0.04        13                                             Terbufos × Primisulfuron                                                                   1.0 × 0.04                                                                          41                                             Terbufos × Primisulfuron +                                                                 1.0 × 0.04                                           2,4-D              0.25        55                                             Terbufos × Primisulfuron +                                                                 1.0 × 0.04                                           2,4-D              0.50        19                                             Terbufos × Primisulfuron +                                                                 1.0 × 0.04                                           2,4-D              0.75        30                                             ______________________________________                                         Shoot height of the untreated check was 73.2 cm                          

EXAMPLE 11

Evaluation of a foliar application of dicamba on the synergisticinteraction between two pesticides

The procedure used is the same as described in Example 3, except thatplants are sprayed with 2-methoxy-3,6-dichlorobenzoic acid (dicamba) andprimisulfuron in sufficient quantities to provide 0-0.5 kg/ha of dicambaand 0.02-0.04 kg/ha of primisulfuron when applied to the plants with a40 psi nozzle.

The results are reported in Table XI.

                  TABLE XI                                                        ______________________________________                                                                       % Growth                                       Treatment          Rate (kg/ha)                                                                              Reduction                                      ______________________________________                                        Untreated check    0.00        0                                              Terbufos           1.00        3                                              Primisulfuron      0.02        6                                              Terbufos × Primisulfuron                                                                   1.0 × 0.02                                                                          34                                             Terbufos × Primisulfuron +                                                                 1.0 × 0.02                                           Dicamba            0.125       15                                             Terbufos × Primisulfuron +                                                                 1.0 × 0.02                                           Dicamba            0.25        12                                             Terbufos × Primisulfuron +                                                                 1.0 × 0.02                                           Dicamba            0.50        29                                             Primisulfuron      0.04        13                                             Terbufos × Primisulfuron                                                                   1.0 × 0.04                                                                          41                                             Terbufos × Primisulfuron +                                                                 1.0 × 0.04                                           Dicamba            0.125       48                                             Terbufos × Primisulfuron +                                                                 1.0 × 0.04                                           Dicamba            0.25        55                                             Terbufos × Primisulfuron +                                                                 1.0 × 0.04                                           Dicamba            0.50        41                                             ______________________________________                                         Shoot height of the untreated check was 73.2 cm                          

EXAMPLE 12

Field evaluation of a foliar application of 2,4-D on the synergisticinteraction between two pesticides

Field trials are conducted in a randomized complete block design withthree replications. Each plot measures 3.05×9.15 meters. Thepreemergence herbicides alachlor and atrazine are applied over theentire plot area at rates of 2.24 and 1.12 kg/ha, respectively. Intreatments containing insecticide, terbufos is applied in-furrow at 1.0kg/ha. The corn variety used in this experiment is LYNKS DS-432.

When the plants have reached the 2-leaf stage, they are sprayed witheither the herbicide nicosulfuron as ACCENT® 75 DF (manufactured byDuPont Co) at 0.036 kg/ha or the herbicide primisulfuron at 0.04 kg/ha,alone or in combination with 0.28 kg/ha of 2,4-D. Applications ofherbicide, with and without a safener compound, are made with atractor-mounted sprayer delivering 224 1/ha.

Ratings are taken six, fourteen and twenty-nine days after postemergencetreatments. Crop injury is evaluated as percent decrease in plant heightand is based on visual observations, in which no injury is assigned a 0%rating, and maximum injury is assigned a 100% rating. Data obtained areaveraged and shown in Table XII.

                  TABLE XII                                                       ______________________________________                                                         % Decrease                                                                    in Plant Height                                              Treatment   Rate (kg/ha)                                                                             6 DAT   14 DAT 29 DAT                                  ______________________________________                                        Untreated check                                                                           0.00       0       0      0                                       Terbufos In-Furrow                                                                        1.00       0       0      0                                       Nicosulfuron                                                                              0.036      0       0      0                                       Terbufos ×                                                                          1.0 × 0.036                                                                        35      23     6                                       Nicosulfuron                                                                  Terbufos ×                                                                          1.0 × 0.036                                                 Nicosulfuron +                                                                2,4-D Amine 0.28       3       0      2                                       Primisulfuron                                                                             0.040      3       0      0                                       Terbufos ×                                                                          1.0 × 0.040                                                                        15      50     27                                      Primisulfuron                                                                 Terbufos ×                                                                          1.0 × 0.040                                                 Primisulfuron +                                                               2,4-D Amine 0.28       6       18     5                                       2,4-D Amine 0.28       0       0      0                                       ______________________________________                                         Terbufos was applied as the 15% granular formulation, COUNTER ® 15G       soil insecticide.                                                             Nicosulfuron was applied as the 75 DF formulation, ACCENT ® herbicide     Primisulfuron was applied as the 75 DF formulation, BEACON ®              herbicide.                                                                    2,4D-Amine was applied as the 4 AS formulation.                          

EXAMPLE 13

Field evaluation of naphthalic anhydride applied directly to theinsecticide on the synergistic interaction between two pesticides

Field trials are conducted in two randomized complete block designs withthree replications each. Each plot measures 3.05×9.15 meters. Thepreemergence herbicides alachlor and atrazine are applied over theentire plot area at rates of 2.24 and 1.12 kg/ha respectively. Terbufosas COUNTER® 15G is applied in-furrow treated and untreated with a 20-40%wettable powder formulation of naphthalic anhydride. The untreatedterbufos is applied at a rate of 1.0 kg/ha. The treated terbufos isapplied at a rate of 1.0 kg/ha of terbufos and 0.125-0.25 kg/ha ofnaphthalic anhydride. The procedure for treating the terbufos is thesame as described in Example 2.

The corn varieties used are DOCKDORF 7670 in the first evaluation andPIONEER 3744 in the second. When the plants have reached the 2-leafstage, they are sprayed with the herbicide primisulfuron at 0.04 kg/ha.Postemergence applications are made with a tractor-mounted sprayerdelivering 224 1/ha.

Ratings are taken at intervals after postemergence treatments. Cropinjury is based on visual observations in which no injury is assigned a0% rating and maximum injury is assigned a 100% rating. Ratings obtainedare averaged and shown in Table XIII.

                                      TABLE XIII                                  __________________________________________________________________________                         % Overall Crop Injury                                                         Trial 1        Trial 2                                   Treatment     Rate (kg/ha)                                                                         14 DAT                                                                             41 DAT                                                                             61 DAT                                                                             30 DAT                                                                             45 DAT                               __________________________________________________________________________    Untreated Check                                                                             0.00   0    0    0    0    0                                    Terbufos In-Furrow                                                                          1.00   0    4    2    0    0                                    Primisulfuron 0.040  0    2    2    0    0                                    Terbufos × Primisulfuron                                                              1.0 × 0.040                                                                    33   40   35   22   18                                   Terbufos × Primisulfuron +                                                            1.0 × 0.040                                               Naphthalic Anhydride                                                                        0.125  0    7    5    15   12                                   Terbufos × Primisulfuron +                                                            1.0 × 0.040                                               Naphthalic Anhydride                                                                        0.25   10   8    8    7    12                                   __________________________________________________________________________

EXAMPLE 14

Field evaluation of naphthalic anhydride applied to the crop seed on thesynergistic interactions between two pesticides

Field trial procedures are repeated as described in Example 13, exceptthat naphthalic anhydride is applied to the corn seed prior to plantingat 0.25% w/w. The seeds are coated as described in Example 1.

The results are shown in Table XIV.

                                      TABLE XIV                                   __________________________________________________________________________                          % Overall Crop Injury                                                         Trial 1        Trial 2                                  Treatment     Rate (kg/ha)                                                                          14 DAT                                                                             41 DAT                                                                             61 DAT                                                                             30 DAT                                                                             45 Dat                              __________________________________________________________________________    Untreated Check                                                                             0.00    0    0    0    0    0                                   Terbufos In-Furrow                                                                          1.00    0    4    2    0    0                                   Primisulfuron 0.040   0    2    2    0    0                                   Terbufos × Primisulfuron                                                              1.0 × 0.040                                                                     33   40   35   22   18                                  Terbufos × Primisulfuron +                                                            1.0 × 0.040                                               Naphthalic Anhydride                                                                        0.25% seed wt                                                                         17   10   8    0    0                                   Naphthalic Anhydride                                                                        0.25% seed wt                                                                         7    3    3    5    2                                   __________________________________________________________________________     Terbufos was applied as the 15% granular formulation, COUNTER ® 15G.      Primisulfuron was applied as the 75 DF formulation, BEACON ®.        

EXAMPLE 15

Evaluation of naphthalic anhydride applied as a seed treatment on thesynergistic interaction between an organophosphate insecticide and apreemergence application of an imidazolinone herbicide

Corn seeds (Pioneer 3475) are treated with naphthalic anhydride(formulated as a 20% wettable powder) by coating with safener at 0.05grams per 100 grams seed (equal to 0.05% by seed weight).

Experiments are conducted in sterilized soil. Soil is placed in10-inch×10-inch×2-inch shallow plastic flats, and thoroughly moistened.Two six-inch furrows are made in each flat, into each are placed fivecorn seeds, either coated or uncoated with the safener. In one series offlats, the organophosphate insecticide terbufos is applied to one furrowas the 15% granular formulation (COUNTER® 15G) at a rate equivalent to 1kg/ha; the other furrow is left untreated. In another series of flats,the organophosphate insecticide phorate is applied to one furrow as the20% granular formulation (THIMET® 20G) at a rate equivalent to 1 kg/ha;the other furrow is left untreated. The flats are sprayed preemergencewith a commercial formulation of the herbicide imazethapyr containing240 mg/mL active ingredient (PURSUIT® 2AS manufactured by AmericanCyanamid Co.) The herbicide is diluted with water to provide theequivalent of 0.025 and 0.05 kg/ha when applied through a spray nozzleoperating at 40 psi for a predetermined time.

After spraying, the flats are placed on greenhouse benches, watered andcared for in accordance with conventional greenhouse procedures.

From 2-4 weeks after treatment, the tests are terminated and each flatis examined and rated by measuring the height of the foliage.

The test results are averaged and expressed as a percent growthreduction compared to an untreated check, as described in Example 1. Thedata obtained are shown in Table XV.

                  TABLE XV                                                        ______________________________________                                                                       % Growth                                       Treatment          Rate (kg/ha)                                                                              Reduction                                      ______________________________________                                        Untreated check    0.0          0                                             Terbufos           1.0          0*                                            Phorate            1.0           0**                                          Imazethapyr        0.025       24                                             Terbufos × Imazethapyr                                                                     1.0 × 0.025                                                                         72                                             Terbufos × Imazethapyr +                                                                   1.0 × 0.025                                                                         34                                             Naphthalic Anhydride                                                                             0.05% w/w                                                  Phorate × Imazethapyr                                                                      1.0 × 0.025                                                                         48                                             Phorate × Imazethapyr +                                                                    1.0 × 0.025                                                                         28                                             Naphthalic Anhydride                                                                             0.05% w/w                                                  Imazethapyr +      0.025        2                                             Naphthalic Anhydride                                                                             0.05% w/w                                                  Imazethapyr        0.05        42                                             Terbufos × Imazethapyr                                                                     1.0 × 0.05                                                                          85                                             Terbufos × Imazethapyr +                                                                   1.0 × 0.05                                                                          41                                             Naphthalic Anhydride                                                                             0.05% w/w                                                  Phorate × Imazethapyr                                                                      1.0 × 0.05                                                                          86                                             Phorate × Imazethapyr +                                                                    1.0 × 0.05                                                                          35                                             Naphthalic Anhydride                                                                             0.05% w/w                                                  Imazethapyr +      0.05        22                                             Naphthalic Anhydride                                                                             0.05% w/w                                                  ______________________________________                                         Shoot height of the untreated check was 64.2 cm                               *Growth was 12% greater than the untreated check.                             **Growth was 2% greater than the untreated check.                        

EXAMPLE 16

Evaluation of naphthalic anhydride applied as a seed treatment on thesynergistic interaction between an organophosphate insecticide and apostemergence application of an imidazolinone herbicide

Corn seeds (Pioneer 3475) are treated with naphthalic anhydride(formulated as a 20% wettable powder) by coating with safener at 0.05grams per 100 grams seed (equal to 0.05% by seed weight).

Experiments are conducted in sterilized loamy sand soil containing 5%organic matter. Soil is placed in 10-inch×10-inch×2-inch shallow plasticflats, and thoroughly moistened. Two six-inch furrows are made in eachflat, into each are placed five corn seeds, either coated or uncoatedwith the safener. The organophosphate insecticide terbufos is applied toone furrow as the 15% granular formulation (COUNTER® 15G) at a rateequivalent to 1.0 kg/ha; the other furrow is left untreated.

Plants are sprayed at intervals ranging from the 2-leaf to the 7-leafstage. A commercial formulation of the herbicide imazethapyr is dilutedwith water to provide the equivalent of 0.035 kg/ha of herbicide to thefoliage when applied through a spray nozzle operating at 40 psi for apredetermined time. The herbicide spray solution contains 0.25% of thespray adjuvant CHARGER E, an alkylaryl polyethoxyethanol and N-butanol80% non-ionic wetting agent manufactured by Blue Ribbon Products Co.Flats are then placed on greenhouse benches, watered and cared for inaccordance with conventional greenhouse procedures.

From 2-4 weeks after treatment, the tests are terminated and each flatis examined and rated by measuring the height of the foliage. The testresults are averaged and expressed as a percent growth reductioncompared to an untreated check, as described in Example 1.

The results are shown in Table XVI.

                                      TABLE XVI                                   __________________________________________________________________________                         % Growth Reduction                                                            Growth Stage at Herbicide Application                    Treatment    Rate (kg/ha)                                                                          2 Leaf                                                                            3 Leaf                                                                            5-6 Leaf                                                                           6-7 Leaf                                    __________________________________________________________________________    Untreated Check                                                                            0.0     0   0   0    0                                           Terbufos     1.0     1   2   2    2                                           Imazethapyr  0.035   16  22  19   29                                          Terbufos × Imazethapyr                                                               1.0 × 0.035                                                                     76  62  44   44                                          Terbufos × Imazethapyr +                                                             1.0 × 0.035                                                Naphthalic Anhydride                                                                       0.05% seed wt                                                                         48  35  40   43                                          Imazethapyr +                                                                 Naphthalic Anhydride                                                                       0.05% seed wt                                                                         13  20  8    21                                          __________________________________________________________________________     Shoot heights of untreated checks were: 64.4 cm (2L); 71.4 cm (3L); 88.4      cm (5-6L); 93.0 cm (6-7L)                                                

EXAMPLE 17

Field evaluation of a foliar application of 2,4-D on the synergisticinteraction between an organophosphate insecticide and a postemergenceapplication of an imidazolinone herbicide

Field trials are conducted as described in Example 12, except that theimidazolinone herbicide imazethapyr (applied as the formulated productPURSUIT® 2AS), is applied postemergence to corn either alone, or incombination with 2,4-D.

The results are shown in Table XVII.

                                      TABLE XVII                                  __________________________________________________________________________                         % Decrease                                                                    in Plant Height                                          Treatment     Rate (kg/ha)                                                                         6 DAT                                                                              4 DAT                                                                              9 DAT                                          __________________________________________________________________________    Untreated check                                                                             0.00   0    0    0                                              Terbufos In-Furrow                                                                          1.00   0    0    0                                              Imazethapyr   0.036  45   24   15                                             Terbufos × Imazethapyr                                                                1.0 × 0.036                                                                    52   89   75                                             Terbufos × Imazethapyr +                                                              1.0 × 0.036                                                                    52   42   18                                             2,4-D Amine   0.028                                                           Terbufos × Imazethapyr                                                                1.0 × 0.036                                                                    55   58   32                                             Terbufos × Imazethapyr +                                                              1.0 × 0.036                                                                    15   13   0                                              2,4-D Amine   0.28                                                            Imazethapyr +                                                                 2,4-D Amine   0.036 + 0.28                                                                         8    7    5                                              __________________________________________________________________________     Terbufos was applied as the 15% granular formulation., COUNTER ® 15G.     Imazethapyr was applied as the 2 AS formulation of PURSUIT ®.             2,4D-Amine was applied as the 4 AS formulation.                          

What is claimed is:
 1. A method of protecting maize or corn from injurywhich comprises applying an effective amount of a safener compound1-carbethoxyethyl-3,6-dichloro-2methoxybenzoate (1) to the plant seed ata rate of at least 0.2% seed weight or (2), to the plant at a rate of atleast 0.125 kg/ha, wherein said safener reduces the phytotoxicsynergistic interaction of a phosphorodithioate insecticide and anacetohydroxyacid synthase-inhibiting herbicide selected from the groupconsisting of sulfonylurea herbicides and imidazolinone herbicides, eachof which is applied in conjunction with said safener compound.
 2. Themethod according to claim 1 wherein the organophosphate insecticide isterbufos or phorate.
 3. The method according to claim 1 wherein theacetohydroxyacid synthase-inhibiting herbicide is primisulfuron.
 4. Themethod according to claim 1 wherein the safener compound is applied tothe corn plant seed.
 5. The method according to claim 1 wherein thesafener compound is applied to the corn plant.
 6. The method accordingto claim 2 wherein the organophosphate insecticide is terbufos.
 7. Acomposition to protect maize or corn from injury which comprises anacetohydroxyacid synthase-inhibiting herbicide selected from the groupconsisting of sulfonylurea herbicides and imidazolinone herbicides, inan amount which is phytotoxic in the presence of a phosphorodithioateinsecticide, and a safener compound1-carbethoxyethyl-3,6-dichloro-2-methoxybenzoate in an amount effectiveto reduce the phytotoxic synergistic interaction of saidphosphorodithioate insecticide and said acetohydroxyacidsynthase-inhibiting herbicide.
 8. The composition according to claim 7wherein the herbicide is primisulfuron.